Search Publications
The Interaction of Successive Coronal Mass Ejections: A Review
Temmer, Manuela; Wang, Yuming; Lugaz, Noé +1 more
We present a review of the different aspects associated with the interaction of successive coronal mass ejections (CMEs) in the corona and inner heliosphere, focusing on the initiation of series of CMEs, their interaction in the heliosphere, the particle acceleration associated with successive CMEs, and the effect of compound events on Earth's mag…
Determining the Intrinsic CME Flux Rope Type Using Remote-sensing Solar Disk Observations
Palmerio, E.; Kilpua, E. K. J.; Green, L. M. +4 more
A key aim in space weather research is to be able to use remote-sensing observations of the solar atmosphere to extend the lead time of predicting the geoeffectiveness of a coronal mass ejection (CME). In order to achieve this, the magnetic structure of the CME as it leaves the Sun must be known. In this article we address this issue by developing…
Understanding the Physical Nature of Coronal "EIT Waves"
Long, D. M.; Veronig, A. M.; Vršnak, B. +9 more
For almost 20 years the physical nature of globally propagating waves in the solar corona (commonly called "EIT waves") has been controversial and subject to debate. Additional theories have been proposed over the years to explain observations that did not agree with the originally proposed fast-mode wave interpretation. However, the incompatibili…
Estimation of Reconnection Flux Using Post-eruption Arcades and Its Relevance to Magnetic Clouds at 1 AU
Gopalswamy, N.; Yashiro, S.; Xie, H. +1 more
We report on a new method to compute the flare reconnection (RC) flux from post-eruption arcades (PEAs) and the underlying photospheric magnetic fields. In previous works, the RC flux has been computed using the cumulative flare ribbon area. Here we obtain the RC flux as the flux in half of the area underlying the PEA in EUV imaged after the flare…
Coronal Holes and Open Magnetic Flux over Cycles 23 and 24
Qiu, Jiong; Lowder, Chris; Leamon, Robert
As the observational signature of the footprints of solar magnetic field lines open into the heliosphere, coronal holes provide a critical measure of the structure and evolution of these lines. Using a combination of Solar and Heliospheric Observatory/Extreme ultraviolet Imaging Telescope (SOHO/EIT), Solar Dynamics Observatory/Atmospheric Imaging …
Observing the Sun with the Atacama Large Millimeter/submillimeter Array (ALMA): High-Resolution Interferometric Imaging
de Gregorio-Monsalvo, I.; Kim, S.; De Pontieu, B. +25 more
Observations of the Sun at millimeter and submillimeter wavelengths offer a unique probe into the structure, dynamics, and heating of the chromosphere; the structure of sunspots; the formation and eruption of prominences and filaments; and energetic phenomena such as jets and flares. High-resolution observations of the Sun at millimeter and submil…
Nonequilibrium Processes in the Solar Corona, Transition Region, Flares, and Solar Wind (Invited Review)
Krucker, Säm; Meyer-Vernet, Nicole; Del Zanna, Giulio +12 more
We review the presence and signatures of the non-equilibrium processes, both non-Maxwellian distributions and non-equilibrium ionization, in the solar transition region, corona, solar wind, and flares. Basic properties of the non-Maxwellian distributions are described together with their influence on the heat flux as well as on the rates of indivi…
Predicting Flares and Solar Energetic Particle Events: The FORSPEF Tool
Papaioannou, A.; Anastasiadis, A.; Kouloumvakos, A. +4 more
A novel integrated prediction system for solar flares (SFs) and solar energetic particle (SEP) events is presented here. The tool called forecasting solar particle events and flares (FORSPEF) provides forecasts of solar eruptive events, such as SFs with a projection to occurrence and velocity of coronal mass ejections (CMEs), and the likelihood of…
Earth-Affecting Coronal Mass Ejections Without Obvious Low Coronal Signatures
Nitta, Nariaki V.; Mulligan, Tamitha
We present a study of the origin of coronal mass ejections (CMEs) that were not accompanied by obvious low coronal signatures (LCSs) and yet were responsible for appreciable disturbances at 1 AU. These CMEs characteristically start slowly. In several examples, extreme ultraviolet (EUV) images taken by the Atmospheric Imaging Assembly onboard the S…
Comprehensive Analysis of the Geoeffective Solar Event of 21 June 2015: Effects on the Magnetosphere, Plasmasphere, and Ionosphere Systems
Fineschi, Silvano; Stangalini, Marco; Bruno, Roberto +34 more
A full-halo coronal mass ejection (CME) left the Sun on 21 June 2015 from active region (AR) NOAA 12371. It encountered Earth on 22 June 2015 and generated a strong geomagnetic storm whose minimum Dst value was −204 nT. The CME was associated with an M2-class flare observed at 01:42 UT, located near disk center (N12 E16). Using satellite data from…